Dealing with cast iron / stress?

[Highpower]

I just got the casting the other day, so I haven't done anything with it yet. I guess I'll see what the heat treat gurus say first, if I can find one locally. The kitchen oven is definitely OUT.

I might just end up roughing it out and then bead blast it. That's the closest thing I have to shot peening since it won't fit in my tumbler.
Let it sit for awhile and see what happens....